Driveshaft problems in BMW 5-Series sedan, panel damage on Mazda 3
Q: I have a 2003 BMW 5-Series sedan and recently I noticed a slight vibration in the vehicle while I was driving on the highway so I took it in to my regular repair shop.
It took some time but they finally found that the driveshaft has a worn universal joint and they believe this is causing the vibration.
They tell me that I need a new driveshaft and the cost for the part is over $1,000! I have owned many vehicles and had universal joints replaced in a couple of them. They never cost me more than about $40 for parts. Is the repair shop ripping me off or has something changed on cars?
A: The repair shop isn’t trying to rip you off. BMW, along with some other auto manufacturers, builds their driveshafts with staked-in universal joints.
At the factory, the joints are assembled in the driveshaft and then small sections of the driveshaft metal are pressed in over the end of the joint to hold it in place.
The joints are not supplied separately as a repair part. Therefore, to get a new universal joint, the dealer will sell you a complete driveshaft. There are alternatives however.
Look for a driveline specialty shop or an automotive machine shop in the yellow pages and contact them to see if they repair your BMW driveshaft.
If they don’t, the shop will likely know which shop in town does do this type of repair.
When you take the driveshaft to this repair shop, they will machine out the stake marks so they can disassemble the universal joint and then press the joint out of the driveshaft. An aftermarket replacement universal joint can then be installed but before doing that, the repair shop needs to do more machining.
Depending on the year and model of the driveshaft and the type of universal joint, there are a couple different machining operations that may need to be performed.
Some universal joints are held in place by spring metal circlips placed against the ends of the universal joint cup.
In order for these to work, the repair shop needs to machine circular grooves in the driveshaft ends in the correct position for these circlips to hold into.
Other types of universal joints are held in by ‘C’ type spring clips that slide into grooves already machined into the cups of the new universal joint.
These clips need to sit against a flat surface on the driveshaft end, so the repair shop must machine the driveshaft to provide these flat surfaces.
You can expect it will cost at least $300 to $400 dollars to have a replacement universal joint installed in this manner but it is much cheaper than a new driveshaft, although not as quick if you need the vehicle all the time.
One advantage of getting the driveshaft machined is that it only needs to be done once.
After that, it only takes less than an hour to install another replacement universal joint.
Q: Heavy rain this summer caused my street to flood and there were branches and debris all over the place.
Fortunately, where I parked my Mazda3, the water only got up to the level of the bottom of the doors but it was like a river was flowing beneath it from the rear.
My problem is that now there is a panel beneath the engine that is almost dragging on the ground. I looked beneath the car but don’t see what is wrong.
How can I fix this?
A: There may be a couple things wrong. First, there could still be debris lodged between the engine and the plastic panel.
The other is that the panel may have broken around the mounting holes or pulled away from the mounting bolts.
First, remove the panel completely. There are a few bolts and clips and it comes off very easy. Then you can clean out any debris that may be forcing it down.
When you reinstall the panel, if any of the mounting holes in the panel are broken, just use a large flat washer to catch more of the panel when you reinstall the bolts that hold the panel up.
If the panel has warped because it has been sitting too long, it can often be fixed by placing it upside down on a flat surface and heating it with a higher power hair drier till the panel sags back flat.